Become a merchant
Three things, and the screen reads all three rather than describing them. There is no application and no identity check — the bond is what is at risk if you do not settle.
A wallet
It signs every advertisement and every settlement, and it is the merchant identity the network sees. There is no account to create and no identity check.
Nothing is connected, so nothing can sign an advertisement.
Use Connect wallet in the header.The merchant bond
Bonded OPEN is what a merchant has at risk if they do not settle. The requirement lives on chain, in the staking program's own config.
Reading the staking program…
Bond OPENOn devnet this step cannot actually be finished: the OPEN mint's authority is permanently unset, so no wallet can obtain any and the token transfer has nothing to move. Creating the stake account works; funding it does not. That is a fact about this cluster, not a limitation of the form.
Somewhere to be paid
At least one account you receive fiat into. When a buyer takes your sell order you nominate one of these, and they see each field separately so they can copy it without retyping.
Reading this browser's saved accounts…
Add a payment accountSaved in this browser and nowhere else. Nothing publishes them, and clearing your site data removes them — so this step is a fact about this device, not about the network.
Where you stand
Connect a wallet to see your advertisements.
Nothing above is enforced by this screen, and the node does not refuse an advertisement from an unbonded wallet. What the bond buys is a counterparty's reason to trust you: it is the stake that is at risk if you take payment and do not release. Posting without it is allowed and visibly unbacked.